The present invention relates to inkjet printing systems, and more particularly, inkjet printing systems which make use of cooling methods to allow an inkjet printhead to operate at very high throughput rates.
Inkjet printing systems frequently make use of an inkjet printhead mounted to a carriage which is moved back and forth across a print media, such as paper. As the printhead is moved across the print media, a control system activates the printhead to deposit ink droplets onto the print media to form images and text. More specifically, ink ejection chambers formed in the printhead eject droplets of ink in a dot matrix pattern. These droplets are ejected by energizing ink ejection elements.
When inkjet printing systems are designed for very high ink flow rate printing, such as those printers for printing large format images, the ink ejection elements generate large amounts of heat. This heat can increase the temperature of the printhead substrate to the point of causing print defects. As the printhead substrate temperature approaches the boiling point of ink, the printhead will cease operating and may sustain permanent damage.
One way to mitigate this problem is to slow down printing when the printhead substrate reaches a critical temperature level. Typically, the printhead will have a thermal sense resistor or equivalent to allow the printing system to monitor substrate temperature. However, slowing down printing is not a "solution"; rather it is a constraint that the present invention is intended to eliminate or minimize.
Accordingly, there is a need to enhance the cooling efficiency of a printhead. Considerations also include the efficiency of printhead assembly, particulate controls during assembly and printhead operation, and air accumulation.